The M4 has been both ways closed as police launch an urgent search.
Officers shut down the motorway between junctions 18 (Bath) and 19 (Bristol) in both directions at 4.30pm this afternoon (Saturday).
A National Police Air Service helicopter is circling an area close to Hinton village, in South Gloucestershire – just metres from the M4. 
It’s understood a car was boxed in by police – resulting in the occupant jumping out and fleeing across nearby fields.
Witnesses claim to have seen a police dog and its handler running across the motorway.
